Gear Coupling Shift Cam Spring Force Minima

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Solution Overview

Problem

Existing clutches for gear and electric monorail systems lack reliable, easy-to-operate, and compact designs, particularly in ensuring secure shift positions and preventing automatic switching, which compromises safety and efficiency.

Innovation Solution

A clutch design featuring a shift cam, a shift element, and a spring element, where the shift element is moved between two positions by rotating the shift cam, with buttons interacting to maintain a local minimum spring force, limiting rotational movement and preventing undefined states, ensuring secure shift positions and easy operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a clutch design uses a shift cam and spring element mechanism, then secure shift positions are achieved, but the device complexity increases

Engineering Contradiction:
Improvesecure shift positionsVSAvoidclutch mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The clutch mechanism is segmented into distinct functional components: shift cam (208), shift element (206), spring element (210), and buttons (20). Each component has a specific function, and their modular arrangement allows for reliable shift positioning while maintaining manageable complexity through clear functional separation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shift cam (208) is designed to rotate between defined angular positions, dynamically transitioning the clutch between engaged and disengaged states. The spring element (210) provides dynamic force that varies with cam rotation, creating local minima at switching positions that securely hold the shift element (210) in place.

Inventive Principle:
Principle #15Dynamics

2Volume of moving object

If the clutch mechanism is made compact, then space is saved, but the ease of operation may be compromised

Engineering Contradiction:
Improveclutch volumeVSAvoidclutch operation ease
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The clutch mechanism achieves compactness by utilizing rotational motion of the shift cam (208) in the angular dimension rather than requiring linear displacement. The shift element (206) moves axially in response to cam rotation, effectively converting rotational movement into axial positioning within a compact volume.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Multiple functions are merged into the shift cam (208) component: it provides the switching action, defines the shift positions through its angular rotation, and controls the spring force variation. This consolidation reduces the number of separate components needed, achieving compactness while maintaining ease of operation through a single actuating motion.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If stop surfaces are added to limit rotational movement, then reliability is improved by preventing undefined states, but the manufacturing complexity increases

Engineering Contradiction:
Improveprevention of undefined statesVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The stop surfaces (201, 202) on the shift cam (208) are pre-positioned during manufacturing to define the angular limits of rotation. This preliminary positioning ensures that the cam can only rotate within the safe angular range, preventing undefined states before operation begins. The stop surfaces physically block rotation beyond the predetermined limits.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If buttons are designed to create local minimum spring force, then secure positioning is achieved, but the precision of button placement requirements increases

Engineering Contradiction:
Improveshift position stabilityVSAvoidbutton placement precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The spring element (210) itself provides the mechanism for secure positioning by creating local minima in force at the desired shift positions. The buttons (20) on the shift cam (208) are positioned to align with these spring force minima, allowing the spring's own characteristics to enforce stable positioning. This self-service approach reduces the need for extremely precise button placement, as the spring force profile naturally creates the stable positions.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The clutch provides secure shift positions, easy operation, and compact integration while preventing automatic switching, enhancing safety and reliability in gear and electric monorail systems, especially during power failures.

Implementation Method 1

a spring element (210), wherein the shift element (206) is shifted between at least two shift positions by rotating the shift cam (208) about the axis of rotation (26) of the shift cam (208) between at least two switching positions against or with a spring force acting on the shift element (206)

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP2715173B1Coupling for a gear mechanism
Publication Date: 2018.11.07 SEW EURODRIVE GMBH & CO KG
  • EP2715173B1 patent drawingFigure 1
  • EP2715173B1 patent drawingFigure 2
  • EP2715173B1 patent drawingFigure 3

AI summary

A coupling for a gear mechanism has a shift cam (14), a shift element (16) and a spring element (18). The shift element (16) can be moved to and fro, by rotation of the shift cam (14) about the rotational axis of the shift cam (14), between at least two shifted positions, counter to or by way of a spring force of the spring element (18), which spring force acts on the shift element. The shift cam (14) has two shifting surfaces. The shifting surfaces interact with the shift element (16) in such a way that the spring force which acts on the shift element (16) attains a local minimum in each shifted position depending on the rotational angle of the rotation.